Printing die



4 April 1, 1930. F. GREFFIN 1,752,293

PRINTING DIE Filed April 6, 1927 l 7m/enfer Pff/L /P GREFF/N 5'@ @MMMTTOENEYS Patented Apr. 1, 1930 .UNITED v'erlrxriis ATENT FFEUE PHILIPPGREFFIN, OF MINNEAPOLIS, MIJ'JBTESOTA,V ASSIGNOB. T0 MELONEBOVEY LUMBERCO., OF MINNEAPOLIS, MINNESOTA, .A CORPORATION 0F MINNESOTA PRINTING DIEApplication inea April e,

This invention relates to the art of embossing and printing, andparticularly relates to that section of embossing art concerned withpressure work through sheet material, with male and female dies-engaging the sheet from opposite sides. The invention is based on thediscovery of a new use of a known material, principally for the purposeof producing what is known in the embossing art as the male die.However, the invention is not considered to be limited tothe productionof male dies, sincethe material possesses qualities permitting of use inany Work where it is the object to compress certain portions of thematerial and cause other portions to be raised, to provide a printingplate or die. no claim is made for the production ofthe material butonly to the discovery of a new property in the material by which it maybe used for the above mentioned purposes.

The main object'of the invention is to provide a. material which, whenacted on by a die, will receive and retain an impression in relief, inwhich the raised portions are of suflicient and of Vequal height toproduce what is known in the embossing art as the male die, and toproduce such a die 'having suflicient rigidity to withstand the unusualand pro-Y longed friction and compression strains well known in thisart, and yet to provide. a die having those qualities which enable it toalso act as a cushion. p

In order to clearly show the economic value of the discovery of theproperties ofthe herein described material, as a medium for the takingof embossed designs, a, presentationr of the method now in general use,is given. In the oldprocess some sort of binder board or othersuitablematerial was used as a base for the male die, and this base wasoverlaid with sheets of paper superposedl one after the other'to buildupthe design upon the base. Thus in the original process, the operationwas mainly that of building up. This operation was performed inthefollowing manner :A metal or female die was prepared having the desireddesign. The next `step was to form the male die. For this purpose, abase was selectedand upon this base was It is to be understood thatl1927. Serial No. 181,450.

first secured a piece of paper of suliicient raised design. This was avery expensive, f

time-consuming process..

It vwill be seen that the difficulty encoun`` f tered in this work is toproduce raised portions of sufficient height andto have all raisedportions of proper height. In addition it has been difficult to lind amaterial' upon which such raised portions could at all be evenlyproduced, and in whichthe raised portions were rigid enough toywithstand the hard usage to which the dieis put. Itwill be understoodthat the operation vof kbuilding upv and re-impressing is veryytime-consumingv and expensive andit is the object of this invention toeliminate the necessity for vthese operations.

To further show the economic value of my discovery a kind of history ofmy own experiments is given. As above stated, orig# inally book binderboard was used. This hoard is composed generally of fibrous woodymaterial such as wood pulp. The attempt was made to produce the raisedor embossed portions by a single, prolonged impression from ya metaldie. rrIt is evident that. if such a thing could be done, the buildingup operation could be entirely dispensed with. l ,How-` ever, in all thematerials experimented withv except the one described herein, .raisedpor..

tions of proper definition and heightcould not be produced except byLbuilding upin the manner' above mentione Attempts lwere made to formthediein another manner, to-wit: by making the impression in plasticmaterial held upon, a suitable Vbase, for example both cement andsealingwax were used.' When usino-fthesesub= stances, a suitable base wasprovidedlandiwas over-laidv with a coat or layer of the sublil() stance,andthe impression was made while in a plastic state. However, 1n theseeases 1t was practically impossible. to obtain an even spread, that isone having equal thickness at all portions. `Moreover, in both cases thecoating would crack under the ordinary working pressures. Thus theobgections were,

poor denition in the embossed areas, andV fracture of the die underpressure. More success was had with cement in regard to the evenness ofthe spreadf but the substance was too brittle to withstanc pressure.lvloreover, although the bases were generally formed of compressiblematerial, this did not prevent cracking of the surface coating.

Experiments were made with another material called bakelite. Sheets ofthis material were used having a thickness of about onesixteenth of aninch. However, this substance was of such density that sufficientclearly defined embossed areas could not be obtained.

Y Moreover, the embossed portions were of uneven height. This material,also, broke down underl pressure, so that a very small number ofimpressions could be made before the die was rendered useless. Thelength of life of thel die could not be depended on as evidenced by thefact that one might only obtain from five to sin impressions. There wasalways the uncertainty as to whether the die would last untiltheir-run77 was completed. Therefore, with using' the above materials,it was practically impossible to obtain clear definition and when somedegree of uniformity or clarity was obtained, the substance would 'crackunder pressure, r

Various so-called builder board materials werealso tried but all werebrittle and acted under the ordinary working pressures, something in themanner of dry lime, that is, they crumbled. The results were fracture,lack of clean definition and lack of sufficient height of the embossedVareas, and uniformity of design, as Well as failure to retain theimpression. Y r

Another board was tried which is also a pulp board but the materials areground and kthe fibre did not have sufficient tensile Lil to me whichwill unfailingly g fined embossed designs of even height and sufficientrigidity, as a result of'a single impression without building up..Moreover, the

rive clearly dematerial is of even texture and can be successfullycarved, that is, without splitting and chipping and without undulydulling `thetools.

A material for use as a male die forthe purpose Vmentioned above musthave a medium length, strong fibre which is sufficientiy long to makethe material tough and to cause it to hold together when beingv cut.After a large number of experiments-it appears that the material mustalso have along line fibre well interwoven in the manner of a felt. Feltitself, however,-is too soft, and does not-,possess sufficient rigidity,nor will such material retain the impression.

The material which l have found to be the best is made from yellow pineinthe following manner: Edgings from yellow pine saw mills containinglive material and no bark, is cut into blocks approximately two inchesVsquare. These blocks or chips are then loaded into what is known as agun, and are submitted to a steam pressure ofY about twelve hundredpounds. The steam carries o some of the resinous material but leavessufficient of natural resinous wood Abinder to obtain a toughcomparatively soft and ycompressible material which can be out `withoutbreaking or cracking. Thus theV natural binding quality of the wood istakenadvantage of and sufficient resinous mattei' is provided so thateach libre is coated with such binder. After the chips have beensubmitted to the pressure above mentioned, vthe gun is shot to releaseand explode the moistened material producing the fine fibre resemblingfine cut tobacco; This `material is then heated and compressed to formthe sheet material, having substantially the properties above described.K

The drawings illustrate the method of making the male die, and thisillustration is only suggestive of .theuse of the present material forthe purpose of making dies orplates for use in the embossing andprinting arts, Y Figure l is an edge view of a sheet of material fromwhich, in this instance, a male embossing die is to vbe constructed;Figure 2 shows the female die making-an impression in the newlydiscovered material; This being the f ust step in the preparationofthedie; n Figure?) is an enlarged view of the .die after theimpression, represented in `Figure 2, and

shows the coating of hardening material` f placed on .the die afterimpression;

Figure 4 is similar to Figure 3 but shows the addition of asheet ofpap-er over-lying and adhesively secured .to the hardening coat. Thisfigure represents thecompleted male die; andV Figure 5 illustrates theoperation of the press showing the male and female die cooperating toproduce an embossed designupon a sheet of material. A Y

The numeral l indicates a sheet ofthe material herein described, ormaterial 'having similar qualities. The numeral 2 indicates a metal die,in embossing Work designated the female die, produced in any suitablemanner. This die is suitablyl mounted so that pressure can be applied.Figure 2 shows the first operation Which is to make an impression on thematerial to form the male die. Figure 3 shows the die after beingimpressed by the metal die 2, and the numeral 3 designates a brushed-onlayer of hardening material, such as Varnish applied directly to theimpressed and embossed surface, and to better enable the raised orembossed portions to stand up under use. lt Will be noted that With thematerial having the qualities set'forth herein, uniformity of design canbe produced, by a single impression. It Will be further noted thatheights exactly corresponding to those of the metal die are produced,and that, therefore, no building up of the raised portions or any of theimpressed part is necessary. lt Will be further understood that in agiven design some parts are given a greater embossed height toaccentuate those parts. lt has been found that all of these resultsmaybe obtainedby a single impression.

Figure 4 shows the completed die in Which further reinforcement isprovided by means of a sheet of ordinary Wrapping paper 4. rfhis sheetis adhesively held and to the coated surface, and in addition toreinforcing the embossed portions, it prevents lpossible contact betweenthe sheet to be embossed, and the hardening layer. lt will thus be seenthat as thev result of feW simple operations, the main one of which is apressure operation. a male die or impression plate is produced in whichproper heights in embossed areas are had, and in Which the embossedportions yare reinforced to With-stand the unusual pressures of themodern presses. The pressure applied is about twenty tons and the lengthof the impression from tvvoto three seconds. @n the old presses, thepressure was substantially instantaneous, and it Was found that With thesubstances like builders board, cel ment or bakelite that theproperimpressions Were seldom, if ever, produced. It has furter been foundthat if the pressing operation is continued, as in the modern type ofpress, that the same difliculty is encountered, that is uniform embosseddesigns ofthe proper height are not produced Without subsequentimpressions and building up with paper or other suitable material. Withthe material herein described every portion of the design is Vproducedin a clean, Well defined manner,

. and Well raised embossed effects are always forthcoming. The materialis very cheap, but the cheapness of material is a small item as comparedwith the time saved on the building-up operation above mentioned. f

Figure rshovvs the operation of producing an embossed vrdesign on asheet of suitable mabossed.

' It will be understood from the description that the propertiesdiscovered in the material n described, as the result of which thematerial will take the impressions in the manner above set forth, formthe main features of my invention. ift will be understood, however, thatl believe myself to be the first to form a die of the characterdescribed which is composed of a single thickness of fibrous material ofhomogeneous consistency and having a comparatively long Well mattedtogether fibre. Some of the'knoivn and essential properties necessaryfor the use set forth herein are: sufficient length of fibre, a naturalresinous binder, combined With a certain density arrived at bycompressing the material to a predetermined extent. `lidoreover, Ibelieve myself the first to make a die of the character describedcomposed of a single thickness of ymatted, compressed cellulosematerial, the

fibres of which are tough and of medium length. Moreover, evenness oftexture is necessary.

Furthermore it is to be understood that by using the material having`substantially the qualities herein set. forth, much Wear and tear on thepress is avoided, vbecause no building up operation is necessary. ItWill be further understood that in the building up operation, as Whenpaper is used and asv before mentioned, the original impressionhavingibe'en made and a sheet ofinate'rial having been laid thereon, anumber of successive pressure` movements Were necessary in order toAVdepress certain portions and raise other v.portions yof the over-laidsheet of' paper, Itvvas necessary to make these impressions severaltimes for each overlay. Thus it can be seen what a great saving is madeboth in the matter of time and in the Wear on the press.y by being ableto obtain a die With asingle impression. l claim as my invention:

A dieconstructed from a material composed of exploded and mattedtogethervwood fibre. r i

2. 'A die constructed from a material com-'v posed of exploded andmatted together pinek Wood fibre.

3. A die constructed from a material com-i'V y posed of exploded andmatted together live yellovvlpine libre.

4. A die constructed from a material composedof exploded'and mattedtogether Wood fibre, the fibre being comparatively long and tough andcontaining a large proportion of f its natural resinous matter.

5. A. die constructed from a material composed of exploded yand mattedtogether yelloW pine Wood fibre, the fibre being comparalesY Y tivelylong and tough and containing a large proportion of its natural resinousmatter.V

6. A die constructed from a material comprising yellow pine fibre inWhich the fibres have been exploded and matted together andv in whichthe libres contain natural resinous Vmaterial as a binder, the saidmaterial after explosion having been heated and compressed.

7. A die constructed from a material comprising live pine fibre in Whichthe fibres have been exploded'and matted together and in which thefibres contain natural resinous material as a binder, the said materialafter explosion having been heated and compressed.

8. A die constructed from a yieldable Inaterial and comprising a toughWood fibre matted together. Y

9. A die constructed from compressible material comprising Wood fibre inwhich the iibres have been exploded and matted together, and in whichthe fibres retain the natural resinous material as a binder. Y

l0. A die constructed from a compressible material consisting ofrelatively tough libre matted together and in Which the fibres retainnatural resinous material as binder, the said material having beenheated and compressed to form a sheet.

11. A die constructed from a yieldable material and composed of a tough,comparatively long Wood fibre matted together.

l2. A die having a base composed of a single thickness of librousmateria-l, said die having an embossed surface, and having a coating ofvarnish-like material over this eml bossed surface, and further having asheet i v my hand this 29th of paper over-lying and adhesively held bythe varnish-like coating.

.13. A die having a base composed of a single thickness of fibrousmaterial of homogeneous consistency, said die having'l an embossedsurface, and having a coating of varirish-like material over thisembossed surface and further having a sheet of paper overlying andadhesively held by the varnishlike coating. V 'Y 1 In Witness whereof, Ihave hereunto set day of March, 1927. PHILIPP GREFFIN.

